Video-on-Demand (VOD) typically refers to an area of technology that allows client device end-users to select video content or other content from a source, such as a central server, for viewing on a suitable end-user display device, such as a television (TV) or a computer monitor. One type of VOD system is a “streaming” VOD system, in which video content or other content is streamed from the source to an end-user client device and viewing of the content can begin as soon as the content streams over a suitable network connection from the source to the end-user client device. Another type of VOD system is a “download” VOD system, in which content initially is downloaded to a video processing device, such as a set-top box, before end-user viewing begins. Typically, almost all download VOD systems and many streaming VOD systems allow the end-user to pause, fast forward, and rewind the content, as well as to view the content at any time.
A VOD server system is typically maintained by a service provider, which can be, for example, a television service provider (e.g., a national or local television network), a cable television service provider or multiple system operator (MSO), an Internet service provider, a satellite broadcast system service provider, or other suitable service provider.
End-users typically desire minimal content download latencies. However, for the service provider, bandwidth requirements typically grow linearly with the number of requests. In some cases, delays can occur even though a service provider provides the required bandwidth.
In addition, a growing population of end-users are interested in social networking and want to easily share viewing information about selected video content (such as favorite, recently viewed, or currently viewed television programs or movies) with their contacts, friends, or connections using social networking portals. Social networking portals include general-interest portals such as Facebook, MySpace, Orkut, Twitter, and Google Buzz, as well as portals specifically directed to social television (e.g., sharing viewing information), such as Tunerfish, Miso, Philo, Clicker Social, and TV.com Relay.